Protein supplementation doesn’t help to keep weight off after weight loss, study suggests

19 Sep 2017 --- Protein supplementation does not result in improved weight management success or blood biochemistry after weight loss compared with the effects of normal dietary protein intake. This is according to a study sponsored by the University of Copenhagen and collaborated on by Danish companies Arla Foods and Nupo A/S.

It had been suggested that protein diets increase weight loss during energy restriction, according to the study authors. Therefore, the point had been made that additional protein intake may improve weight maintenance after weight loss. Past research on the importance of protein in weight management included a 2015 study which suggested that “higher-protein diets […] provide improvements in appetite, body weight management, cardiometabolic risk factors or all of these health outcomes.”

The researchers investigated the effect of protein supplements from either whey – with or without calcium – or soy on weight management success after weight loss compared with that of a control.

“When looking at the consensus of studies, they generally show that protein still plays an important role in relation to weight management,” Heidi Kildegaard, Nutrition Specialist in Global Nutrition at study cosponsor Arla Foods, tells NutritionInsight in reaction to the study results. “Looking at this specific study, the results most likely reflect the fact that the protein intake was primarily in liquid form and it is likely that the results would have been different if the protein was part of more solid food.”

Protein supplementation on trial
In the randomized, controlled, double-blinded trial, 220 participants aged 18 to 60 with body mass index (in kg/m2) from 27.6 to 40.4 were included. The study was initiated with an eight-week weight loss period followed by a 24-week weight management period.

During weight management, participants consumed the following four isocaloric supplements in amounts of 45 to 48g per day: whey and calcium (whey plus), whey, soy or maltodextrin (control). Data were collected at baseline, before weight management and after weight management (weeks 0, 8 and 32, respectively) and included body composition, blood biochemistry and blood pressure.

Meal tests were also performed to investigate diet-induced-thermogenesis and appetite sensation. The researchers tested compliance by 24-hour urinary nitrogen excretion.

A total of 151 participants completed the weight management period, the researchers report. The control and three protein supplements did not result in different mean weight regain, fat mass regain or improvements in lean body mass during weight management. Changes in blood pressure and blood biochemistry were not different between groups.

The researchers also note that compared with the control, protein supplementation resulted in higher diet-induced thermogenesis (around 30 kJ/2.5 h) and resting energy expenditure (243 kJ/d). It also resulted in an anorexigenic appetite-sensation profile.

Protein explored further
Protein still has many uses in the diet, according to Kildegaard. “Among other things, protein contributes to the growth and maintenance of muscle mass, as well as the maintenance of normal bones. Protein is also needed for normal growth and development of bone in children. There is also a general scientific agreement that protein has an effect on satiety,” she notes.

There are also several ongoing studies on protein supplementation both in and outside Arla Foods. “To mention a few, Arla participates in studies indicating that a diet with higher protein at the expense of carbohydrate is beneficial to diabetic consumers. We are also involved in studies that examine the influence of milk proteins on appetite regulation and weight, as well as protein and malnutrition, protein and sport," Kildegaard adds.

The options for protein supplementation certainly remain plentiful and varied. NutritionInsight spoke to Troels Laursen of Arla Foods about the company’s crystal-clear whey protein water at the IFT Food Expo 2017 in Las Vegas.

“Traditionally, whey protein has had some difficulties in ready to drink beverages, but we have developed a whey protein that works very well in a ready to drink formulation,” Laursen says. Glanbia also won an award at IFT 2017 for its BevEdge Pea Protein, which can mix easily into beverages.

NutritionInsight has explored the topic of high-protein diets in a special report looking at the views of suppliers, benefits like muscle mass and drawbacks like potential medical issues.

By Paul Creasy